Backstop and Infielder

Backstop noun - (baseball) the person who plays the position of catcher.

Infielder and backstop are semantically related. In some cases you can use "Infielder" instead a noun "Backstop".

Infielder noun - (baseball) a person who plays a position in the infield.

Backstop and infielder are semantically related. Sometimes you can replace term "Backstop" with "Infielder", this nouns are similar.